To be fair, the Switch changed the storage medium and Wii and Wii U disks are bigger than the console itself. That is not to say that Nintendo has not had multiple storage mediums compatible with the same consoles, for example: Gamecube miniDVDs and Wii DVDs working with the Wii and Gameboy cartridges and Gameboy Advance Cartridges working with the Gameboy Advance. But I think I am willing to cut Nintendo some slack for the Switch given the many compromises they must have made to fit that much power into a hand-held unit.

I am sour however that the Wii Remotes are not working with the Switch though, as I find the Wii Wheel to be a superior experience when playing Mario Kart. There is no technical reason for this as far as I can tell as the Switch still uses Bluetooth for connectivity. Now, there are new wheels, but just like the Joy-Cons, they are far too small to be comfortable given the size of my hands.

I've been pairing the Wii Remotes to my laptop, and playing the old games that way via Dolphin!

I do this as well with a mayflash sensor bar. Dolphin also works for rock band and guitar hero which has been pretty fun.

Very late reply so you might never see this... but I have a full complement of RB and GH hardware, and a long-term project I'm investigating is ensuring those rhythm games can always be played via Dolphin even once all the 'toy' hardware is dead and buried.

Specifically: I want to add direct support for proper e-drums played via MIDI into Dolphin, without the various hacks to get it to emulate a keyboard etc, and compatible even with the Pro Drums mode in RB3.

Guitars are simultaneously an easier and harder question: would require a DIY guitar, but can be fed into Dolphin just by emulating a HID device.

email is in my bio if you want to discuss

Yup, and it was wonderful. The Wii also had the virtual console for older titles that worked great, but some of those didn't make the transition and you have to re-purchase them (if I'm not mistaken, they are always online subscription based titles)

I think you can still play SNES games on the Wii, you just need to modify the console.

You can do pretty much anything on the wii. It was so successful and so easy to crack and mod that it's got everything you'd want, including virtual console injections

Gameboys had backwards compatibility as well, at least for a while. Probably half the games I ever played on my gameboy color were released for the original gameboy. Playstations also had backwards compatibility at around the same time.